U.S. patent number RE48,618 [Application Number 16/502,878] was granted by the patent office on 2021-06-29 for radio frequency transceiver.
This patent grant is currently assigned to ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. The grantee listed for this patent is ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE. Invention is credited to Yong-Il Jun, Jong-Won Kim, Hyeong-Ho Lee, Bong-Hyuk Park.
United States Patent |
RE48,618 |
Park , et al. |
June 29, 2021 |
Radio frequency transceiver
Abstract
Provided is a radio frequency transceiver. The radio frequency
transceiver includes: a receiving unit for converting a radio
frequency signal received by an antenna into an intermediate signal
based on an intermediate local signal; a transmitting unit for
converting an intermediate signal into a radio frequency signal
based on a radio frequency local signal; and a local signal
generating unit for generating the intermediate local signal and
the radio frequency local signal.
Inventors: |
Park; Bong-Hyuk (Daejeon,
KR), Kim; Jong-Won (Daejeon, KR), Jun;
Yong-Il (Daejeon, KR), Lee; Hyeong-Ho (Daejeon,
KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE |
Daejeon |
N/A |
KR |
|
|
Assignee: |
ELECTRONICS AND TELECOMMUNICATIONS
RESEARCH INSTITUTE (Daejeon, KR)
|
Family
ID: |
1000005416599 |
Appl.
No.: |
16/502,878 |
Filed: |
July 3, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
10831633 |
Apr 22, 2004 |
7542731 |
Jun 2, 2009 |
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Foreign Application Priority Data
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Jul 16, 2003 [KR] |
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10-2003-0048805 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04B
1/28 (20130101); H04B 1/405 (20130101) |
Current International
Class: |
H04B
1/28 (20060101); H04B 1/405 (20150101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1998026710 |
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Jul 1998 |
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KR |
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20020047542 |
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Jun 2002 |
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KR |
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Primary Examiner: Choi; Woo H.
Claims
What is claimed is:
1. An apparatus for transmitting/receiving a radio frequency
signal, comprising: a receiving means for converting a radio
frequency signal received by an antenna into an intermediate signal
based on .[.an intermediate frequency (IF) band local signal.].
.Iadd.a radio frequency (RF) band local signal.Iaddend.; a
transmitting means for converting an intermediate signal into a
radio frequency signal based on .[.a radio frequency (RF).].
.Iadd.the RF .Iaddend.band local signal; and a local signal
generating means for generating .[.the IF.]. .Iadd.an intermediate
frequency (IF) .Iaddend.band local signal and the RF band local
signal, wherein said local signal generating means includes: a
phase locked loop (PLL) for both the receiving means and the
transmitting means for selecting a channel to reduce interference
with the radio frequency signal; a voltage control oscillator for
generating a first local signal based on the channel selected by
the PLL; a multiplier for multiplying the frequency of the first
local signal by a predetermined number to generate a multiplied
signal; an amplifier for amplifying the multiplied signal to
generate the RF band local signal; a divider for dividing the
frequency of the first local signal by a predetermined number to
generate a divided signal; and a phase shifter for shifting a phase
of the divided signal to generate the IF band local signal.
2. The apparatus as recited in claim 1, wherein said receiving
means includes: a low noise amplifier for amplifying the received
signal to generate an amplified radio frequency signal; a
down-converter for converting the amplified radio frequency signal
into the intermediate signal by combining the .[.amplitied.].
.Iadd.amplified .Iaddend.radio frequency signal and the .[.IF.].
.Iadd.RF .Iaddend.band local signal; a receiving gain controller
for controlling a level of the intermediate signal; a demodulator
for demodulating the intermediate signal based on the IF band local
signal to generate an in-phase signal and a quadrature-phase
signal; a filter for removing radio frequency noises included in
the in-phase signal and the quadrature-phase signal, to thereby
generate a filtered in-phase signal and a quadrature-phase signal;
and an analog-to-digital (A/D) converter for converting the
filtered in-phase signal and the quadrature-phase signal to digital
in-phase and quadrature-phase signals.
3. The apparatus as recited in claim 1, wherein said transmitting
means includes: a digital-to-analog (D/A) converter for converting
.[.the.]. signals from .[.the.]. .Iadd.a .Iaddend.baseband modem to
analog signals; a modulator for modulating the analog signals into
intermediate signals based on the IF band local signal to generate
a modulated signal; a transmitting gain controller for controlling
a level of the modulated signal to generate a gain controlled
signal; an up-converter for converting the gain controlled signal
which is in IF band to a radio frequency signal based on the RF
band local signal; and an amplifier for amplifying the radio
frequency signal.
4. The apparatus as recited in claim 1, further including:
switching means for allowing one of said receiving means and said
transmitting means to be operated; and filtering means for removing
noise of the .[.transmission.]. .Iadd.radio frequency
.Iaddend.signal and the received signal.
Description
FIELD OF THE INVENTION
The present invention relates to a radio frequency transceiver;
and, more particularly to a radio frequency transceiver which uses
a voltage control oscillator and a phase locked loop for both of a
transmitting unit and a receiving unit of the transceiver, and
reduces the number of components and chip size of the
transceiver.
DESCRIPTION OF RELATED ART
FIG. 1 is a diagram showing a conventional transceiver.
As shown, in a transmitting unit of the conventional transceiver,
an in-phase signal and a quadrature-phase signal, which are
converted from digital signals to analog signals in a baseband
modem (not shown), are mixed with a local signal from a local
oscillator (LO) in up-converters 111 and 112 to generate radio
frequency signals, amplified in a power amplifier (PA) 113,
filtered in a bandpass filter (BPF) 102 and radiated through an
antenna 101.
In a receiving unit of the conventional transceiver, a signal
received by the antenna 101 is transferred to a low noise amplifier
(LNA) 105 through the BPF 102, a balance to unblance transformer
(Balun) 104. The received signal is amplified in the LNA 105, mixed
with signals generated by the LO 109 to generate an intermediate
signal in a mixer 109. The intermediate signal is modulated in down
converters 107 and 108 based on the four-divided signal of the
local oscillation signal to generate an in-phase signal and a
quadrature-phase signal.
In the conventional transceiver, a different local oscillator is
used for the transmitting unit and the receiving unit, and the
oscillation signal generated for the transmitting unit raises
interference at the receiving unit, to thereby decrease performance
of the transceiver.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a
radio frequency transceiver which uses a voltage control oscillator
and a phase locked loop for both of a transmitting unit and a
receiving unit of the transceiver, and reduces the number of
components and chip size of the transceiver.
In one aspect of the present invention, there is provided an
apparatus for transmitting/receiving a radio frequency signal,
including: a receiving unit for converting a radio frequency signal
received by an antenna into an intermediate signal based on an
intermediate local signal; a transmitting unit for converting an
intermediate signal into a radio frequency signal based on a radio
frequency local signal; and a local signal generating unit for
generating the intermediate local signal and the radio frequency
local signal.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and features of the instant invention
will become apparent from the following description of preferred
embodiments taken in conjunction with the accompanying drawings, in
which:
FIG. 1 is a diagram showing a conventional transceiver;
FIG. 2 is a diagram depicting a transceiver in accordance with an
embodiment of the present invention; and
FIG. 3 is a diagram illustrating a transceiver in accordance with
another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Other objects and aspects of the invention will become apparent
from the following description of the embodiments with reference to
the accompanying drawings, which is set forth hereinafter. Here,
the same reference numeral is given to the same element, even
though it appears in different drawings.
FIG. 2 is a diagram depicting a transceiver in accordance with an
embodiment of the present invention.
As shown, the transceiver includes an antenna 201, a bandpass
filter 202, a switch 203, a receiving unit 210, a transmitting unit
220, a local signal generating unit 230, and a baseband modem
250.
The transmitting unit 220 receives a digital signal outputted from
the baseband modem 250, transmits a radio frequency (RF) signal,
and includes digital-to-analog (D/A) converters 221 and 222, an
in-phase and quadrature-phase (IQ) modulator 223 and 224, a
transmitting automatic gain controller (AGC) 225, an up-converter
224 and an amplifier 226.
The digital signals from the baseband modem 250 is converted into
analog signals to generate an analog in-phase signal and an analog
quadrature-phase signal in the D/A converters 221 and 222. In the
IQ modulator 223 and 224, the analog in-phase signal and the analog
quadrature-phase signal are modulated based on a signal of which a
center frequency is F5 and combined to generate a modulated signal.
A gain of the modulated signal is controlled in the transmitting
AGC 225, converted into an intermediate signal based on a signal of
which a center frequency is F4 in the up-converter 226 and
amplified by an amplifier 227. The amplified intermediate signal is
transmitted by the antenna 201 through the bandpass filter 202.
The receiving unit 210 includes a low noise amplifier 211, a
down-converter 212, a receiving automatic gain controller (AGC)
213, IQ demodulators 214 and 216, bandpass filters 215 and 217,
analog-to-digital (A/D) converters 218 and 219.
A signal received by the antenna 201 is transmitted to the low
noise amplifier 211 to be amplified through the bandpass filter 202
and the switch 203. In the down-converter 212, the amplified signal
is converted into an intermediate signal based on a local signal
generated by the local signal generating unit 230. The center
frequency of the local signal is F5. The intermediate signal is
demodulated to generate an in-phase (I) signal and a
quadrature-phase (Q) signal in the IQ demodulators 214 and 216, and
then transferred to the baseband modem 250 through the bandpass
filters 215 and 217 and the A/D converters 218 and 219.
The local signal generating unit 230 generates local signals and
includes a phase locked loop (PLL) 231, a voltage controlled
oscillator (VCO) 232, a multiplier 233, an amplifier 234, a divider
235 and a phase shifter 236.
A transmission channel is selected in the PLL 231, and a local
signal of which a center frequency is F3 is generated for the
selected channel in the VCO 232. The local signal is multiplied by
2 to generate a signal of which the center frequency is F4 in the
multiplier 233 and divided by 2 to generate a signal of which the
center frequency is F5 in the multiplier 235.
The center frequency F5 is obtained by equations as: F1(or
F2)-2.times.F3=F5 Eq. (1) F5-F3/2 Eq. (2)
FIG. 3 is a diagram illustrating a transceiver in accordance with
an embodiment of the present invention. In this embodiment, the
transceiver is for a 5 GHz radio local area network (LAN) which is
based on IEEE802.11a standard.
The radio LAN transceiver sets a radio frequency 5,785 MHz, which
is one of 12 transmission channels.
When transmitting a signal, the digital signal from the baseband
modem 350 is converted into analog signal to generate an analog
in-phase signal and an analog quadrature-phase signal in the D/A
converters 321 and 322. In the IQ modulators 323 and 324, the
analog in-phase signal and the analog quadrature-phase signal are
modulated based on a second local signal of which a center
frequency is 1,157 MHz and combined to generate a modulated signal.
A gain of the modulated signal is controlled in the transmitting
AGC 325, converted into an intermediate signal based on a third
local signal of which a center frequency is 4,628 MHz in the
up-converter 326 and amplified by an amplifier 327. The amplified
intermediate signal is transmitted by the antenna 301 through the
bandpass filter 302.
In the receiving unit 310, a receiving level is detected by a
received signal strength indicator (RSSI) 318 and transmitted to
the baseband modem 350. The baseband modem 350 provides a control
signal to a receiving AGC 313 to maintain the receiving level as a
predetermined value.
If the PLL 331 of the local signal generator selects the eleventh
channel, the voltage controlled oscillator 332 generates a first
local signal of which center frequency is 2,314 MHz. The first
local signal is multiplied and divided by two to generate the
second local signal and the third local signal. The third local
signal is transmitted to the up-converter 326 and the
down-converter 312. The second local signal is transmitted to the
IQ modulator 323, 324 and the IQ demodulator 314, 315.
In the IEEE802.11a standard, frequencies of 5 GHz RF band, a local
band and an IF band in each channel are expressed in Table 1.
TABLE-US-00001 TABLE 1 Channel No. RF band (MHz) Local band (MHz)
IF band (MHz) 1 5180 2072 1036 2 5200 2080 1040 3 5220 2088 1044 4
5240 2096 1048 5 5260 2104 1052 6 5280 2112 1056 7 5300 2120 1060 8
5320 2128 1064 9 5745 2298 1149 10 5765 2306 1153 11 5785 2314 1157
12 5805 2322 1161
In the heterodyne radio frequency transceiver in accordance with
the present invention, the same voltage controlled oscillator (VCO)
and the phase locked loop (PLL) generate both of an RF band signal
and an IF band signal, and then the transceiver has smaller number
of components. Accordingly, the transceiver has a simple structure,
a low manufacturing expense. If the transceiver is manufactured as
a one-chip, the chip size can be considerably reduced. Further,
because the intermediate frequency is different from the frequency
of the VCO in the receiving unit, DC offset is reduced and the
performance of the transceiver is increased.
While the present invention has been described with respect to
certain preferred embodiments, it will be apparent to those skilled
in the art that various changes and modifications may be made
without departing from the scope of the invention as defined in the
following claims.
* * * * *